In an effort to build support for his signature economic stimulus plan, Mr. Obama is setting off for Indiana on Monday, holding his first prime-time news conference on Monday night and heading to Florida on Tuesday.

He also is hoping to refill his reservoir of political capital and escape Washington after a bruising week in the White House.

A collection of private and public polls, as well as focus groups convened by Democratic strategists, showed that the public’s support for the economic recovery package was eroding [...]